1. Field of the Invention
The present invention relates to a thermoplastic resin composition. More particularly, it pertains to a thermoplastic resin composition well suited for the formation of industrial materials such as electric and electronic materials, industrial construction material, automobile parts and domestic electrical appliances.
2. Description of the Related Arts
Various thermoplastic resins have heretofore been improved in heat resistance, dynamical properties, dimensional stability and hygroscopicity by compounding therein an inorganic filler or an different resin. In the field of engineering plastics, investigation for such improvement and practical application have been made on polyester, polyamide, polycarbonate and the like. Further improvement, however, is desired with increasing demand for heat resistance and water resistance in recent years. On the other hand, a styrenic polymer having syndiotactic configuration has recently been developed and attracted special interest as an engineering plastics provided with heat resistance and water resistance. Nevertheless, the above-developed styrenic polymer having syndiotactic configuration is still insufficient in rigidity and impact strength, and further improvement in heat resistance is eagerly desired.
For the purpose of further improving the dynamical properties and heat resistance of the styrenic polymer having syndiotactic configuration (hereinafter sometimes referred to as "syndiotactic polystyrene"), the group of the present inventors has already proposed a method by blending an inorganic filler (Japanese Patent Application Laid-Open No. 257948/1987) and a method for improving adhesion to an inorganic filler (Japanese Patent Application Laid-Open Nos. 258855/1990 and 126743/1991). The methods have exhibited prominent effect on the improvement as compared with conventional techniques, but have still been imperfect in the effect, leaving some room for further improvement.
Particularly in the latter proposal, there have been used atactic polystyrene and a polymer having a polyphenylene ether in its skeleton that are compatible with the syndiotactic polystyrene in order to improve the adhesiveness between the syndiotactic polystyrene and an inorganic filler. However, the aforesaid polymers have been poor in heat resistance as compared with the syndiotactic polystyrene, sometimes causing the possibility of inhigiting crystallization. The syndiotactic polystyrene compounded with the polymer having a polyphenylene ether skeleton has suffered the disadvantage that the long-term heat resistant stability of the syndiotactic polystyrene composition has been deteriorated to a great extent.
In addition, the group of the present inventors investigated a polymer alloy of the syndiotactic polystyrene and an other resin (polyamide, PET or PBT) and tried to improve the syndiotactic polystyrene composition in impact resistance and elongation thereof as well as the other resin in hygroscopicity, dimensional stability, heat resistance and rigidity. As a result, there has been a limit in the improvement effect because of the inevitable deterioration of the dynamical properties arising from the insufficiency of the particle size dispersion and interfacial strength, since the composition consists of the resins that are inherently incompatible with each other. Such being the case, there was proposed by the aforesaid group a method wherein atactic polystyrene and a polymer having a polyphenylene ether in its skelton were used as compatibilizers (Japanese Patent Application Laid-Open No. 126744/1991). After all the above-mentioned problem still remains unsolved in the use of the compatibilizers as proposed above.
Under such circumstances, intensive research and investigation were continued by the present inventors in order to develop an adhesive, a compatibilizer and a syndiotactic polystyrene composition using the same each being excellent in water resistance, impact resistance, heat resistance, modulus of elasticity and dynamical properties and capable of improving the adhesiveness to an inorganic filler and compatibility with other resins without impairing the crystallization of the syndiotactic polystyrene and deteriorating the long-term heat resistant stability of the same.